The Gulf Coast petrochemical industry, already bruised by trade tensions with China, faces higher costs, shrinking profits and tougher market access from the new round of tariffs imposed by the Trump administration, putting thousands of American jobs and billions of dollars in capital investments at risk if the trade war with China escalates.

Energy and chemical companies have poured billions of dollars into building petrochemical plants to take advantage of region’s cheap supplies of natural gas and access to international markets through the Houston Ship Channel. Many of those huge investment decisions were based on the expectation that Chinese demand for chemicals would swell.

But on Friday, the United States increased tariffs from 10 percent to 25 percenton $200 billion worth of Chinese goods and China promised it would retaliate. Petrochemical companies now face the possibility that the Chinese demand on which they planned could evaporate, leading to rising supplies of global and falling prices.